As a rule, power semiconductor modules are mounted on a heat sink for cooling. In addition, these modules may be connected to electrical circuiting means such as, e.g., printed circuit boards or busbars to externally connect them. This is why the module and the heat sink need to be mechanically aligned and thermally contacted to corresponding thermal contact surface to make the contact. It is particularly when making use of viscous and heat-conductive paste between the module and the heat sink, e.g., a heat-conductive paste, that it may happen that the module becomes twisted relative to the heat sink, resulting in the heat-conductive as originally defined in its thickness distribution becoming smudged, rendering its application haphazard.
This is particularly a problem when just a single fastener, such as a screw, is used to conjoin the power semiconductor module to the heat sink, although even when two or more fasteners are used this may be a problem due to the threaded hole needing to be sufficiently oversized to facilitate threading the screws. In this case too, the module may become twisted relative to the heat sink, smudging the heat-conductive pastes.
Therefore, one aspect of the present invention is thus to provide a power semiconductor module which can now be mounted reliably twist-secured on a heat sink. A further aspect involves a method of mounting a power semiconductor module reliably twist-secured on a heat sink.